Organocatalytic Asymmetric Allylic Alkylation of Morita–Baylis–Hillman Carbonates with Diethyl 2‑Aminomalonate Assisted by In Situ Protection

With
the aid of in situ protection by N-(2-formylphenyl)-4-methyl-benzenesulfonamide,
enantioselective allylic alkylation of Morita–Baylis–Hillman
carbonates with diethyl 2-aminomalonate was successfully realized.
The corresponding adducts can be obtained in up to 99% yield with
up to 98% ee as well as excellent regioselectivity. Besides, the adducts
with opposite configurations were readily prepared by utilizing easily
available and inexpensive quinine or quinidine as organocatalyst.
Facile deprotection of the resulting adduct provides straightforward
access to enantiopure α-methylene-γ-lactam.